1. Field of the Invention
The present invention relates generally to an apparatus and a related network for communicating packets of electronic signals among a collection of nodes, and more particularly, to an apparatus and a related network for routing respective packets of electronic signals to respective nodes in a collection.
2. Description of the Related Art
There has been an increasing use of local area networks to provide centralized management and control over related functions performed at spatially dispersed locations. Typical earlier local area networks comprised collections of nodes and means for coupling the nodes in the collection to one another so that packets of information-carrying electronic signals could be routed among the nodes. The respective packets ordinarily included routing signals used by the respective nodes to identify which node was the destination or target for respective individual packets. Thus, respective packets of information carrying signals typically were transferred from node to node in the network until they reached their respective destination nodes.
One well known technique for guiding a respective packet of signals among the nodes of a local area network involves including routing signals in the packet which identify the destination node for the respective packet. Briefly stated, as the respective packet is transferred from node to node, each node examines the identifying routing signals in order to ascertain whether that node is the destination for the respective packet. If it is, then it processes the packet of signals. If it is not, then it transfers the packet to another node in the network. Although sometimes nodes are included in a network which select between two or more other nodes as the next node for receiving the respective packet, the selection ordinarily is made based upon a predetermined routing path to be followed by a respective packet in reaching its destination node, and that routing path typically is not easily modified.
While prior local area networks generally have been successful, there have been shortcomings with their use. For example, in constructing a local area network, it is important to couple respective nodes of the network so that respective packets can be transferred among the nodes. In the past, such coupling usually involved connecting conductor wires between respective nodes of the network which were to transfer packets between one another. However, the spatial layout of the nodes within the network sometimes could be complex, and when the network was to be installed in a preexisting structure such as a hotel building or a factory, the wiring together of respective nodes could result in significant disruption and expense. Furthermore, there often was a possibility that one or more nodes within the network might fail or that there might be a need to change the predetermined routing path in order to add new nodes or to delete unwanted nodes. Unfortunately, such changes to hard wired networks could be difficult and expensive to accomplish.
One alternative approach to providing centralized management and control over related functions performed at spatially dispersed locations involves the provision of radio frequency signals modulated by respective information carrying packets of signals. The respective modulating packets include identifying signals used to identify the respective destination nodes for the respective packets. Instead of transferring respective packets in a stepwise node to node fashion, packets are broadcast directly to their respective destination nodes. While using this alternative approach ordinarily does not require that individual nodes be wired together, and therefore, can lead to easier installation of networks in complex layouts and in preexisting structures, there have been problems with its use. These problems result from the possibility of simultaneous broadcasts of radio frequency signals by different nodes which can result in interference between the simultaneously broadcasted signals. The potential interference problems attendant with simultaneous broadcasts can necessitate that transmission of packets by nodes be restricted so as to not result in simultaneous broadcasts. However, restricting nodes so as to broadcast only when they will not interfere with broadcasts by other nodes can reduce the volume of packets which can be provided using radio frequency signals.
Furthermore, often there are stringent licensing requirements governing the use of certain radio frequency signals. Thus, the use of radio frequency signals to couple a network of dispersed nodes can require potentially time consuming efforts to obtain appropriate licenses to use signals of a particular frequency.
Thus, there has existed a need for an apparatus and a related local area network which can be easily and economically installed even in an environment involving a complex layout of a network of nodes in preexisting structures, which can be used to route packets of information carrying signals in a flexible manner so that routing paths among nodes can be changed or modified easily and which includes redundancy in case of individual node failures. The present invention meets these needs.